Study Estimates Ten Gigatonnes of Scrubber Washwater Released Annually

May 19, 2021
Public Relations

Study Estimates Ten Gigatonnes of Scrubber Washwater Released Annually

May 19, 2021

A new study is shedding light on the impact and just how much scrubber washwater is being discharged into the oceans annually and the numbers are staggering. The International Council on Clean Transportation’s (ICCT) latest report estimates that scrubber fitted ships emit at least 10 gigatonnes (Gt) (ONE gigatonne is equal to 1,000,000,000,000 kilograms!) of scrubber wash water each year! The amount is so large that it is almost incomprehensible. To put it into perspective, that is nearly equivalent to the total quantity of payload the maritime industry transports on a yearly basis at 10.7 Gt of goods per year. Also consider, that is enough scrubber washwater to fill 4,000,000 (four million) Olympic-size swimming pools.

What’s more shocking is that ICCT researchers report this figure to be conservative. The study’s authors examined the cumulative effects of only 3,600 ships fitted with scrubbers. The total number of scrubbers in use has since climbed to over 4,300. Researchers also assumed an open-loop discharge rate of just 45 t/ MWh. While the IMO considers this to be a normalized discharge rate, the actual rate is far greater for most ships. A small solace is that the study’s authors relied on pre-pandemic traffic patterns. Some portions of the shipping sector still haven’t recovered from the pandemic. This is especially true for the cruise line industry where no-sail orders remain in effect. When these orders do lift however, the ICCT’s startling estimate will only grow. That means, each year, over 10 Gt of toxic and highly acidic water will be dumped into the oceans. That is 10 Gt of polluted water containing things like polycyclic aromatic hydrocarbons (PAHs), particulate matter, nitrates, nitrites, and heavy metals, all of which will wreak havoc on marine life before making their way to us.

While the sheer amount of scrubber washwater is troublesome alone, researchers are also concerned about where these discharges are accumulating. Shipping traffic is not spread around the world evenly. In congested areas, scrubber discharges tend to be significantly higher than less popular places. It makes sense than, that ICCT researchers determined that 80% of scrubber discharges occur within 200 nautical miles of shore. They also noted that hot spots are arising in heavily trafficked regions like the Baltic Sea, North Sea, Mediterranean Sea, Caribbean Sea and the Strait of Malacca.

Perhaps most concerning is the 665 million tonnes of scrubber washwater being dumped in Particularly Sensitive Sea Areas (PSSAs). The IMO grants PSSA status to some of the world’s most vulnerable places. While there are a number of regulations imposed within these areas, shipping is still permitted. Even worse, there are no limits on scrubber discharges. According to the ICCT report, of the fifteen IMO-designated PSSAs, only one is completely spared from scrubber washwater. Researchers marked Malpelo Island as safe for now but given that it is the smallest PSSA, this provides little comfort. As for the other PSSAs, Western European waters, the Baltic Sea and the Great Barrier Reef fared by far the worse, experiencing the highest quantities of scrubber discharges. That is a big problem and particularly so for the Great Barrier Reef where the situation is already dire. Just earlier this month, a new study predicted that 94% of coral reefs could be errored by 2050. The addition of scrubber washwater will just further seal the Great Barrier Reef’s fate.

So who is to blame for all this destruction? ICCT researchers estimated that 70% of scrubber discharges can be attributed to container ships, bulk carriers, and oil tankers. Cruise ships account for another 15% of these discharges worldwide. That is especially startling given that cruise ships represent only 4% of the scrubber-equipped fleet. What’s more is that ICCT researchers determined that cruise ships are responsible for the vast majority of scrubber discharges in port. In seven of the ten ports with the overall highest scrubber discharges, cruise ships accounted for at least 96% of it. Now, ICCT researchers did derive these numbers from pre-pandemic travel patterns. With much of the cruise industry waiting for no-sail orders to lift, the estimates may be a bit high. Still, this could be a glimpse of the near future and it most certainly looks grim.

The ICCT study gives us 10 gigatonnes of reasons as to why our scrubber regulations need an overhaul. Let’s make the necessary changes before it is too late!

scrubber-discharges-Apr2021.pdf ( by LIUDMILA OSIPOVA, PH.D., ELISE GEORGEFF, AND BRYAN COMER, PH.D.

Coral reefs could stop growing in 10 years unless greenhouse gases are significantly reduced, new study says – ABC News ( by JULIA JACOBO

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